ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The influence of magnesium, phosphorus, and iron additions on the low-temperature (≤1000°C) sintering of nanocrystalline α-Al2O3 derived from α-AlOOH has been investigated. α-AlOOH powder with a surface area of 50 m2/g yielded α-Al2O3 products with surface areas of 150 and 80 m2/g after dehydration at temperatures of 400° and 500°C, respectively. However, these products were prone to sintering at 〉600°C, and the surface area was reduced to 15 m2/g within only 1 h at 1000°C. Although magnesium and iron doping had no discernible effect, the presence of phosphorus inhibited sintering and surface-area loss significantly. Samples doped with 1%–2% phosphorus had surface areas of 〉31 m2/g after 100 h at 1000°C. Atomic force microscopy studies of α-Al2O3 pseudomorphs derived from α-AlOOH single crystals also demonstrated the inhibiting effect of phosphorus, as the rate of crack elimination was reduced on phosphorus-modified surfaces. The effects of the dopants are discussed with regard to their potential influence on α-Al2O3 surface energy and diffusivity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.2002.tb00455.x
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